Simple Tips for Maintaining Stainless Steel

Posted by Darrell Nicholson at 01:43PM - Comments: (3)

Patrick Childress
Patrick Childress

A toothbrush helps apply cleaning paste in crevices and hard-to-reach tight spots.

Moisture with little or no oxygen invites rust. Salt, which helps to hold moisture, is a catalyst for the process. This is why rust normally starts at the base of bedded stainless-steel hardware, at longitudinal joins of rolled handrails, or in pitted areas. Welded areas have a higher susceptibility to corrosion, because heating stainless can destroy its “stainless” qualities. That’s why it is better to cut stainless steel by hand with a hacksaw than with an electric cutting wheel, which overheats the metal, causing stainless steel to rust where it was cut.

Polishing discoloration from stainless steel can actually wipe away evidence of impending doom. Colored dye test kits and a magnifying glass can help to detect defects in stainless steel that lead to failure. But even new stainless hardware can unexpectedly fail. Stainless chainplates and mast tangs are notorious failure points due to cyclical loading and corrosion penetration at minute cracks. Our special report “Marine Metal Warning,” delved into this topic.

Patrick Childress
Patrick Childress

For tough stains, a 3M scrubby pad helps loosen rust stains.

To get a brilliant, long-lasting finish, manufacturers of high-grade marine hardware give their 304 and 316 products an electropolish. Electro-polishing involves bathing metal in a mild acid with an electric current. This takes away all the impurities and makes the stainless shine. Old stainless-steel hardware can be removed from your boat to be electro-polished again.

Even if you don’t electro-polish, you can bring stainless back to a shiny condition that helps ward off corrosion. Brightening the stainless also gives you an opportunity to inspect the hardware.

What stainless-steel deck hardware likes best is plenty of fresh water and mild soap to rinse away moisture-retaining salt and grime. On long, rainless ocean passages, it can be helpful to scrub down the decks, even with buckets of seawater, to reduce the concentration of salt residue. To eliminate the salt without wasting precious water, follow this rinse by wiping down with a wet rag soaked in fresh water. Don’t use chlorine cleaners as these are highly corrosive.

Getting out the shinola kit and buffing stainless steel before it rusts is a good practice. When rust has developed, buffing is still an easy exercise.

Patrick Childress
Patrick Childress

The results of our labor before . . .

Patrick Childress
Patrick Childress

. . . and after.

Our test of rust-stain removers showed that the most effective cleaners usually contained phosphoric acid or oxalic acid. Pastes are preferable. A jar of runny cleaner can spill easily, and any acid must be thoroughly rinsed, since the acid can harm gelcoat.

When applying a paste cleaner, a toothbrush is useful for buffing tight spots and working into the pores of welds; follow by buffing with a cotton cloth. A green, 3M scrubby pad helps remove more aggressive stains. Continued rusting in welded areas might indicate developing failure, requiring replacement. Rinse thoroughly with fresh water and mild soap when done buffing.

Applying one of our favorite cleaner waxes or one of the best polish-protectants from our metal polish test will help protect against corrosion, but, this protection doesn’t last long. One of our top-rated corrosion-block sprays will offer slightly better protection, but some of these products are quite sticky, so they will pick up dirt.

All this close, hands-on attention not only keeps the stainless looking bright but can prevent a major failure of the rigging. The close work makes it easier to inspect components, and the cleaning will often uncover cracked turnbuckles, wire end fittings, and other hardware problem before they fail.

For more on cleaning stainless and dealing with other problem boat stains, check out our e-book “Essential Cleaners,” part of a three-part series on marine cleaners.

Comments (3)

spotless stainless primary active ingredient is acetic acid.

Posted by: Chriscod | September 30, 2018 3:46 PM    Report this comment

Hi, I work in the nuclear industry and use a lot of stainless steel. One of the problems is that when you machine or drill or grind any 300 series stainless steel, which appears to be what was shown in the article, atomic level iron particles are imbedded in the stainless base metal. A lot of them. They rust quickly, which is what you see on most any boat. The parts must be passivated to remove all elemental iron and restore the stainless, non corrosive surfaces. Passivation will do this permanently. However, it is not easy for most people. Here it is and it requires removing the stainless parts from EVERYTHING ELSE.

This is extracted from Federal Specification QQ-P-35C, which you can find on line for free. (All government documents are free to US tax payers, except printed paper versions.) Parts must be completely clean of oil, dirt, etc. You must wear protective thick rubber gloves, goggles and a rubber or plastic apron. This stuff will eat most everything, including skin and eyes. HAZARDOUS!!

"Para 3.3.6, Type VI. Solution shall contain 25-45 percent by volume of nitric acid (HNO3). Parts shall be processed for 30 minutes at a temperature range of 70-90 deg. F."

After 30 minutes soaking, drop the part in clean water or rinse with lots of water. It is safe to handle or reinstall at this point.

You can put one end at a time in the solution if you want to passivate a stanchion or something long.

Another nearly as useful method used by welders after completing a weld is to use commercial pickling gel. This is almost as nasty to work with but does not run. So you can paint it on a spot and wait per instructions. McMaster Carr has it, p/n 8554T11 for about $70 per quart. Welder supply houses have it, too. (You will likely never run out.) It must be flushed with lots of fresh water after the time expires. HAZARDOUS!!

Both of these should solve all the rust on stainless problems on your parts. Do NOT put iron or any other metals into the solution.

Cleaning because of other residues and dirt is still required.

Good luck and BE CAREFUL. Charlie Williams

Posted by: chasmains | April 23, 2014 1:17 PM    Report this comment

There are a lot of metal cleaners. I have tried a lot with mixed results.

I didn't see this product tested before, but might be worth checking into it. Spotless Stainless

I tried it after seeing it mentioned in an online forum post.

it worked shockingly well. As with any product, key is application. if it dries, it stops working. I apply it with a small brush and cover it with some plastic wrap. For small pieces (shackles, pins etc) I put some of the cleaner in a plastic zip lock lunch bag with the parts..massage the bag til they are coated.

With either method, leave for a few minutes (or as I do, over night) and rinse the next day. Like new!

There is no wax, so a good polish or wax would be good too. But does get into all the cracks, screw slits, and welds quite well, with close to zero effort.

With just time and warmth (needs to be somewhat warm for it to work) and some water to rinse, it has worked well for me.

it does easily bleach the teak deck, so some care has to be taken, but the teak naturally ages again.

I have used it to get rust stains off other parts with no ill effect.

No doubt there are other similar products like this, but this does work well


Posted by: Phantomracer | April 23, 2014 10:41 AM    Report this comment

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